The present disclosure is related to wellbore operations and, more particularly, to intelligent casing collars and cement wiper plugs used in wellbore cementing operations.
During completion of oil and gas wells, cement is often used to solidify a well casing within the newly drilled wellbore. To accomplish this, cement slurry is first pumped through the inner bore of the well casing and either out its distal end or through one or more ports defined in the well casing at predetermined locations. Cement slurry exits the well casing into the annulus formed between the well casing and the wellbore, and is then pumped back up toward the surface within the annulus. Once the cement hardens, it forms a seal between the well casing and the wellbore to protect oil producing zones and non-oil producing zones from contamination. In addition, the cement bonds the casing to the surrounding rock formation, thereby providing support and strength to the casing and also preventing blowouts and protecting the casing from corrosion.
Prior to cementing, the wellbore and the well casing are typically filled with drilling fluid or mud. A cementing plug is then pumped ahead of the cement slurry in order to prevent mixing of the drilling mud already present within the wellbore with the cement slurry. When the cementing plug reaches a float collar or cement plug arranged within the casing at a predetermined location, the hydraulic pressure of the cement slurry ruptures the cement plug and enables the cement slurry to pass through the plug and then through either the distal end of the casing or the side ports and into the annulus. Subsequently, another cementing plug is pumped down the casing to prevent mixing of the cement slurry with additional drilling mud that will be pumped into the casing following the cement slurry. When the top cementing plug lands on the casing collar or the cement plug, the pumping of the cement slurry ceases.
Prior to, during, and following the cementing operation, it may prove advantageous to monitor and transmit various wellbore parameters relating to the cementing operation to ensure that operations are proceeding and completed as designed.